Large-scale generation of electric power based on a freely-available essentially inexhaustible natural resource, such as solar irradiance, continues progressing as an attractive modality for clean and efficient generation of electric power. A photovoltaic array may be typically made up of photovoltaic modules (e.g., solar panels), which may be electrically connected in series circuit to form strings connected to one or more inverters, which supply alternating current (AC) power to a power grid. Performance of the photovoltaic modules may degrade over time. For example, if the performance of a photovoltaic module degrades excessively, other modules that are connected in series circuit with the degraded module (e.g., in a string of modules) may end up providing suboptimal performance.
Therefore, one way to maximize energy yield would be to install monitoring devices to detect underperforming modules and subsequently replace such underperforming modules. Conventional technologies for monitoring individual PV modules often are centralized (e.g., involving a central data collection station) and consequently tend to be complex and economically costly. For example, use of wireless devices which may be used to communicate large amounts of data (e.g., from hundreds or even thousands of PV modules) to the central data collection station tend to be costly and complex to maintain. Techniques that involve irradiance sensors as a reference for monitoring performance of a PV module may be vulnerable to contamination of such sensors, such as due to dirt, etc.
In view of the foregoing considerations, it would be desirable to provide improved methodology and apparatus for registering conditions of performance in a photovoltaic array.